1/*
2 * Copyright (C) 2011 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "CrossfadeGeneratedImage.h"
28
29#include "FloatRect.h"
30#include "GraphicsContext.h"
31#include "ImageBuffer.h"
32
33namespace WebCore {
34
35CrossfadeGeneratedImage::CrossfadeGeneratedImage(Image* fromImage, Image* toImage, float percentage, const FloatSize& crossfadeSize, const FloatSize& size)
36    : m_fromImage(fromImage)
37    , m_toImage(toImage)
38    , m_percentage(percentage)
39    , m_crossfadeSize(crossfadeSize)
40{
41    setContainerSize(size);
42}
43
44static void drawCrossfadeSubimage(GraphicsContext* context, Image* image, CompositeOperator operation, float opacity, const FloatSize& targetSize)
45{
46    FloatSize imageSize = image->size();
47
48    // SVGImage resets the opacity when painting, so we have to use transparency layers to accurately paint one at a given opacity.
49    bool useTransparencyLayer = image->isSVGImage();
50
51    GraphicsContextStateSaver stateSaver(*context);
52
53    context->setCompositeOperation(operation);
54
55    if (useTransparencyLayer)
56        context->beginTransparencyLayer(opacity);
57    else
58        context->setAlpha(opacity);
59
60    if (targetSize != imageSize)
61        context->scale(FloatSize(targetSize.width() / imageSize.width(), targetSize.height() / imageSize.height()));
62    context->drawImage(image, ColorSpaceDeviceRGB, IntPoint());
63
64    if (useTransparencyLayer)
65        context->endTransparencyLayer();
66}
67
68void CrossfadeGeneratedImage::drawCrossfade(GraphicsContext* context)
69{
70    // Draw nothing if either of the images hasn't loaded yet.
71    if (m_fromImage == Image::nullImage() || m_toImage == Image::nullImage())
72        return;
73
74    GraphicsContextStateSaver stateSaver(*context);
75
76    context->clip(FloatRect(FloatPoint(), m_crossfadeSize));
77    context->beginTransparencyLayer(1);
78
79    drawCrossfadeSubimage(context, m_fromImage, CompositeSourceOver, 1 - m_percentage, m_crossfadeSize);
80    drawCrossfadeSubimage(context, m_toImage, CompositePlusLighter, m_percentage, m_crossfadeSize);
81
82    context->endTransparencyLayer();
83}
84
85void CrossfadeGeneratedImage::draw(GraphicsContext* context, const FloatRect& dstRect, const FloatRect& srcRect, ColorSpace, CompositeOperator compositeOp, BlendMode blendMode, ImageOrientationDescription)
86{
87    GraphicsContextStateSaver stateSaver(*context);
88    context->setCompositeOperation(compositeOp, blendMode);
89    context->clip(dstRect);
90    context->translate(dstRect.x(), dstRect.y());
91    if (dstRect.size() != srcRect.size())
92        context->scale(FloatSize(dstRect.width() / srcRect.width(), dstRect.height() / srcRect.height()));
93    context->translate(-srcRect.x(), -srcRect.y());
94
95    drawCrossfade(context);
96}
97
98void CrossfadeGeneratedImage::drawPattern(GraphicsContext* context, const FloatRect& srcRect, const AffineTransform& patternTransform, const FloatPoint& phase, ColorSpace styleColorSpace, CompositeOperator compositeOp, const FloatRect& dstRect, BlendMode blendMode)
99{
100    std::unique_ptr<ImageBuffer> imageBuffer = ImageBuffer::create(size(), 1, ColorSpaceDeviceRGB, context->isAcceleratedContext() ? Accelerated : Unaccelerated);
101    if (!imageBuffer)
102        return;
103
104    // Fill with the cross-faded image.
105    GraphicsContext* graphicsContext = imageBuffer->context();
106    drawCrossfade(graphicsContext);
107
108    // Tile the image buffer into the context.
109    imageBuffer->drawPattern(context, srcRect, patternTransform, phase, styleColorSpace, compositeOp, dstRect, blendMode);
110}
111
112}
113